Commonly-owned U.S. Pat. No. 5,074,016 to Meyer details a widely-used machine, known as a “stuffer box,” for crimping textile threads. Described as part of the machine are a compression chamber, a decompression chamber, and pivoting paddles defining an evacuation, or holding, chamber. Spring blocks or similar structures may bias the paddles to a normally-closed position, initially closing the outlet.
Textile thread introduced into the machine via drive pulleys (e.g. nip rolls) packs into the compression chamber, with the act of compression facilitating crimping of the threads. Additional thread forced into the machine drives crimped thread from the compression chamber into the decompression chamber, where the crimped thread is subjected to an atmosphere of hot steam (or other appropriate fluid). Subjecting the thread to vapor in this manner assists in fixing the crimps in the thread.
Thereafter, the fixed, crimped thread is forced into the evacuation chamber. Doing so counteracts force provided by the spring blocks so that the paddles open slightly. As the paddles open, thread may exit the machine for further processing or to be wound onto a winding machine or other device.
Machines detailed in the Meyer patent function well in use. Desirably, however, these machines could provide increased throughput of crimped threads. One possible way of increasing throughput is to increase the height of the machine, thereby increasing the volumes of the compression, decompression, and evacuation chambers. Increasing the volumes of the chambers obviously increases the amount of thread positionable in each chamber. Unfortunately, however, it also decreases the uniformity of the crimping, an undesirable result.
Another possible technique for increasing throughput is to expand the width of the machine. Enlarging the width of the stuffer box allows for relatively uniform crimping of the threads, thus avoiding the problem associated with increasing the height of the machine. Regrettably, though, a width increase mandates a corresponding resizing of the nip rolls. Such resizing exacerbates the ability of one thread to slide relative to another, producing different entry speeds of threads into the stuffer box. The different entry speeds in turn create exit difficulties associated with the threads and their subsequent winding.